The present invention relates to apparatus for handling flat articles and, more particularly, to apparatus for turning the position of a flat article from a longitudinal posture to a short posture, during the transportation of such an article.
In an apparatus for handling a flat article, such as a mail envelope or a post card, the position of the flat article is frequently turned from a longitudinal posture to a short posture, during the transportation thereof. For instance, the flat article is transferred with the longitudinal posture parallel to the direction of travel in a transport path, during a postal code reading operation. However, during a final sorting operation, it is transferred with the short posture parallel to the direction of travel, so that stackers may be arranged in a high density to stack the flat articles.
According to a prior art technique, such turning of the flat article posture is performed by two cone rollers or by one cone roller and a plurality of idler rollers which have the same diameter and which engage the conical surface of the cone roller to clamp the flat article therebetween. In the rotation of the cone roller, the turning of the flat article posture is effected because the peripheral rotation speed of the cone roller varies according to the surface position along the length of the cone roller. However, in the prior art technique, an overly wide clamping angle is formed in the nip between the two cone rollers or between the cone roller and the idler rollers is too wide. Therefore, there was an imperfect clamping operation therebetween. Consequently, the flat article has not been accurately turned at 90.degree., and this inaccurateness causes a jam in the transportation system.